This invention relates to a smoking device which may perform to decrease smoke current generated from a burning point of cigarette, namely side stream smoke, when the cigarette is not puffed under the lit condition.
Smoke current, generated when smoking, comprises two kinds; primary smoke current exhaled by a smoker and side stream smoke generated from the burning point of cigarette. It is well known that this side stream comes to be inhaled by people near the smoker and badly affects them. In this connection, it is known that the ratio of the injurious substances contained in the primary smoke current and side stream smoke is described as shown in the following table I.
TABLE I ______________________________________ Ratio of injurious substances in side stream Injurious substances smoke and primary smoke current ______________________________________ Tar 2.1-3.4 Nicotine 1.8-2.8 Benzopylen 3.9 Carbon monoxide 4.7 ______________________________________
As the table I is self-explanatory, the quantity of injurious substances contained in the side stream smoke is twice or three times higher than that in the primary smoke current, thus it comes that the non-smokers who are consequently compelled to inhale the side stream smoke because being near the smoker, are exposed to suffer from harm to their health more than the smoker himself does.
As one measures against the side stream smoke, the inventors of this invention have developed a certain technique enabling a smoking instrument to arrest the generation of side stream smoke, and have suggested a smoking device for it.
In other words, a burning point of cigarette is inserted into and held in a cylinder having a plurality of openings on the peripheral wall so as to arrest the side stream smoke generated from the burning point of cigarette. Such a technique has been developed and disclosed in U.S. Pat. No. 4,638,819.